Large psuedo-stored fields via BinaryDocValuesField

(sub-issue of SOLR-10117) This is a proposal for a better way for Solr to handle "large" text fields. Large docs that are in Lucene StoredFields slow requests that don't involve access to such fields. This is fundamental to the fact that StoredFields are row-stored. Worse, the Solr documentCache will wind up holding onto massive Strings. While the latter could be tackled on it's own somehow as it's the most serious issue, nevertheless it seems wrong that such large fields are in row-stored storage to begin with. After all, relational DBs seemed to have figured this out and put CLOBs/BLOBs in a separate place. Here, we do similarly by using, Lucene BinaryDocValuesField. BDVF isn't well known in the DocValues family as it's not for typical DocValues purposes like sorting/faceting etc. The default DocValuesFormat doesn't compress these but we could write one that does.